The current cost distribution of a crystalline silicon PV module is clearly dominated by material costs, especially by the costs of the silicon wafer. Therefore cell designs that allow the use of thinner wafers and the increase of energy conversion efficiency are of special interest to the PV industry. This article gives an overview of the most critical issues to achieve this aim and of the recent activities at Fraunhofer ISE and other institutes.

S. W. Glunz

High-Efficiency Crystalline Silicon Solar Cells

A simplified nanosphere lithography process has been developed which allows fast and low-waste maskings of Si surfaces for subsequent reactive ion etching (RIE) texturing. Initially, a positive surface charge is applied to a wafer surface by dipping in a solution of aluminum nitrate. Dipping the positive-coated wafer into a solution of negatively charged silica beads (nanospheres) results in the spheres becoming electrostatically attracted to the wafer surface. These nanospheres form an etch mask for RIE. After RIE texturing, the reflection of the surface is reduced as effectively as any other nanosphere lithography method, while this batch process used for masking is much faster, making it more industrially relevant.

Daniel Inns

Patrick Campbell

Kylie Catchpole

Wafer Surface Charge Reversal as a Method of Simplifying Nanosphere Lithography for Reactive Ion Etch Texturing of Solar Cells

During maskless ion etching of amorphous glass, self-organization
can arise in certain etch parameter ranges,
which leads to dense-lying dots/cones with typical diameters
and heights in the 30&#x2013;300&#8201;nm range. Another
phenomenon, which results in cone sizes around 1&#8201;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x03BC;</mml:mi></mml:math>m
or more, is self-masking especially in the case of heterogeneous
glasses like borosilicate glass as used in this
contribution. Thus, a wide range of characteristic sizes
and shapes of individual scatterers on the glass surface,
jointly acting as a defined roughness, can be achieved
resulting in specific optical scattering characteristics. This contribution gives results on borosilicate thin-glass
dry etching. Certain surface morphologies are reported
together with experimental results on their optical
scattering characteristics.

Henning  Fouckhardt

Ingo  Steingoetter

Matthias  Brinkmann

Malte  Hagemann

Helmut  Zarschizky

Lin  Zschiedrich

nm- and <svg style="vertical-align:-3.56265pt" height="12.175" version="1.1" viewBox="0 0 9.5625 12.175" width="9.5625" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><path id="x1D707" d="M538 96q-38 -45 -84 -76.5t-71 -31.5q-44 0 -15 117q12 49 18 89h-2q-99 -128 -163 -178q-36 -28 -70 -28q-26 0 -44 38h-2q-16 -69 -16 -129q0 -43 11 -75.5t24 -42.5l1 -6q-7 -12 -24.5 -23t-37.5 -11q-40 0 -40 76q0 52 35 202l94 407l78 24l5 -5q-32 -122 -72 -310&#xA;q-7 -33 0 -55t25 -22q36 0 105.5 75t107.5 145l32 146l75 26h10q-50 -197 -78 -347q-7 -38 6 -38q7 0 31 17t47 39z" /></g></svg> m-Scale Surface Roughness on Glass with Specific Optical Scattering Characteristics on Demand

The two-component kinetic model employing &#8220;fast&#8221; and &#8220;slow&#8221; metastable defects for the annealing behaviors in pin-type hydrogenated-amorphous-silicon- (a-Si:H-) based solar cells is simulated using a normalized fill factor. Reported annealing data on pin-type a-Si:H-based solar cells are revisited and fitted using the model to confirm its validity. It is verified that the two-component model is suitable for fitting the various experimental phenomena. In addition, the activation energy for annealing of the solar cells depends on the definition of the recovery time. From the thermally activated and high electric field annealing behaviors, the plausible microscopic mechanism on the defect removal process is discussed.

Seung Yeop Myong

Annealing Kinetic Model Using Fast and Slow Metastable Defects for Hydrogenated-Amorphous-Silicon-Based Solar Cells

This paper gives a review of some recent developments in the field of contactless silicon wafer 
    characterization techniques based on lifetime spectroscopy and infrared imaging. In the first part of the 
    contribution, we outline the status of different lifetime spectroscopy approaches suitable for the 
    identification of impurities in silicon and discuss&#x2014;in more detail&#x2014;the technique of temperature- and 
    injection-dependent lifetime spectroscopy. The second part of the paper focuses on the application 
    of infrared cameras to analyze spatial inhomogeneities in silicon wafers. By measuring the infrared 
    signal absorbed or emitted from light-generated free excess carriers, high-resolution recombination 
    lifetime mappings can be generated within seconds to minutes. In addition, mappings of 
    non-recombination-active trapping centers can be deduced from injection-dependent infrared lifetime 
    images. The trap density has been demonstrated to be an important additional parameter in the 
    characterization and assessment of solar-grade multicrystalline silicon wafers, as areas of increased 
    trap density tend to deteriorate during solar cell processing.

Jan Schmidt

Peter Pohl

Karsten Bothe

Rolf Brendel

Advances in Contactless Silicon Defect and Impurity Diagnostics Based on Lifetime Spectroscopy and Infrared Imaging

We demonstrate new series of heavy metal containing fluorophosphate glass system. The fluorescence and nonradiative properties of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow><mml:mtext>Nd</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>
 ions are investigated as a function of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Nd</mml:mtext></mml:mrow><mml:mtext>2</mml:mtext></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> concentration. The variation of intensity parameters <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>&#x03A9;</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>&#x03A9;</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>&#x03A9;</mml:mi><mml:mn>6</mml:mn></mml:msub></mml:mrow></mml:math> is determined from absorption spectra. The spontaneous probability <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mi>A</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> and branching ratio <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mi>&#x03B2;</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> are determined using intensity parameters. The emission cross sections for the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mi></mml:mi><mml:mn>4</mml:mn></mml:msup><mml:msub><mml:mi>F</mml:mi><mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:mrow></mml:msub><mml:mo>&#x2192;</mml:mo><mml:msup><mml:mi></mml:mi><mml:mn>4</mml:mn></mml:msup><mml:msub><mml:mi>I</mml:mi><mml:mrow><mml:mrow><mml:mrow><mml:mn>13</mml:mn></mml:mrow><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:mrow></mml:msub></mml:mrow></mml:math> transition, which is calculated by Fuchtbabauer-Ladenburg method, decrease from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>6.1</mml:mn><mml:mo>&#x00D7;</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>21</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>3.0</mml:mn><mml:mo>&#x00D7;</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>21</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msup><mml:mrow><mml:mtext>pm</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msup></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> and those for the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mi></mml:mi><mml:mn>4</mml:mn></mml:msup><mml:msub><mml:mi>F</mml:mi><mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:mrow></mml:msub><mml:mo>&#x2192;</mml:mo><mml:msup><mml:mi></mml:mi><mml:mn>4</mml:mn></mml:msup><mml:msub><mml:mi>I</mml:mi><mml:mrow><mml:mrow><mml:mrow><mml:mn>11</mml:mn></mml:mrow><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:mrow></mml:msub></mml:mrow></mml:math> transition decrease from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>3.51</mml:mn><mml:mo>&#x00D7;</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>20</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1.7</mml:mn><mml:mo>&#x00D7;</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>&#x2212;</mml:mo><mml:mn>20</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Nd</mml:mtext></mml:mrow><mml:mtext>2</mml:mtext></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> concentration increase up to 3 wt<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>. The nonradiative relaxation is analyzed in terms of multiphonon relaxation and concentration quenching due to energy transfer among <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow><mml:mtext>Nd</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>
 ions. Finally, the above results obtained at 1 wt <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Nd</mml:mtext></mml:mrow><mml:mtext>2</mml:mtext></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>
 are compared with some of reported laser host glasses which indicated the potentials for broadband-amplifiers and high-power laser applications.

Ju H. Choi

Alfred  Margaryan

Ashot  Margaryan

Frank G. Shi

Wytze Van Der Veer

Fluorescence and Nonradiative Properties of  Nd<sup>3+</sup>  in Novel Heavy Metal Contained Fluorophosphate Glass

A theoretical study is presented of guided modes of a photonic crystal waveguide for cases in which they interact with multiple bound electromagnetic modes localized on off-channel impurity features of Kerr nonlinear media. The interest is on
the properties of resonant scattering and optical bistability exhibited by the system and the coherent scattering of the guided modes due to their simultaneous resonant interactions with multiple bound modes. In first study, two off-channel features on opposite sides of a photonic crystal waveguide are made of different Kerr nonlinear dielectric media. In second study, an off-channel feature is composed of two neighboring sites having different Kerr dielectric properties. In addition to numerical results
a number of analytical results are presented providing simple explanations of the quantitative behaviors of the systems. A relationship of these systems to forms of electromagnetic-induced transparency and modifications of waveguide dispersion relations is discussed.

A. R. McGurn

Photonic Crystal Waveguide Weakly Interacting with Multiple Off-Channel Resonant Features Formed of Kerr Nonlinear Dielectric Media

We describe the operation of a semiconductor-superlattice parametric oscillator (SPO) at a subterahertz frequency (near 300 GHz). The oscillator is driven by a microwave source (frequency near 100 GHz). We also present an analysis indicating that operation at frequencies above 1 THz should be possible. The SPO is based on the ability of conduction electrons in a superlattice to perform Bloch oscillations. Broadband tunability as well as the monochromacy of a driving microwave field are transferred to the SPO.

Karl F. Renk

Andreas Rogl

Benjamin I. Stahl

Matthias Muthmann

Helmut Appel

Manish Jain

Anatoly Glukhovskoy

Dieter Schuh

Werner Wegscheider

Semiconductor-Superlattice Parametric Oscillator as a Subterahertz and Possible Terahertz Radiation Source

The optical properties of metal-organic vapor phase epitaxy grown <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Al</mml:mtext></mml:mrow><mml:mi>y</mml:mi></mml:msub><mml:msub><mml:mrow><mml:mtext>In</mml:mtext></mml:mrow><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mrow><mml:mtext>Ga</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>&#x2212;</mml:mo><mml:mi>x</mml:mi><mml:mo>&#x2212;</mml:mo><mml:mi>y</mml:mi></mml:mrow></mml:msub><mml:mtext>N</mml:mtext></mml:mrow></mml:math> quantum dot structures have been studied by time-resolved photoluminescence experiments. We investigated the recombination dynamics of the photo-exited carriers in dependence of the growth parameters such as aluminium flow and the duration of the growth interruption after the dot deposition. Our results confirm the presence of localized states, where the degree of localization is strongly dependent on the growth conditions. To describe this behavior, we propose a band structure with coupled potentials for these nanostructures. Finally, we demonstrate state filling to prove the zero-dimensional character of the strongly localized states in our quaternary quantum dots.

A.  Gr&#246;ning

V.  P&#233;rez-Sol&#243;rzano

M.  Jetter

H.  Schweizer

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<p>Advances in OptoElectronics publishes papers on the theory, design, fabrication, and applications of devices and components that convert light into an electrical current or, conversely, an electric current into light.</p>


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Advances in OptoElectronics ceased publication in 2019 and is no longer accepting submissions.

description

Advances in OptoElectronics publishes papers on the theory, design, fabrication, and applications of devices and components that convert light into an electrical current or, conversely, an electric current into light.

Advances in OptoElectronics